Process for the manufacture of nitrate of lime in globular form



Nov. 1934- N. STEPHANSEN ET AL 1,982,549

PROCESS FOR THE MANUFACTURE OF NITRATE 0F LIME IN GLOBULAR FORM I Filed Feb. 16, 1953 Patented Nov. 27, 1934 PROCESS FOR THE' MANUF NITRATE F LIME IN GLOB Nicolai Stephansen, Rjukan;

Eyer, Ludwigshafen-on- Moder, Munster-on- .signors to Norsk Hydro Aktieselskab, Oslo,

Application F 3 Claims.

It is known that it is possible by the addition of nitrate-of ammonia to aconcentrated solution of nitrate of lime to obtain a product containing 15.5 to 16% nitrogen and solidifying at a much 5 higher temperature than the Norgesalpeter (nitrate of lime with 13% nitrogen).

It is also known that it is possible by spraying the said solution of nitrate of lime having an addition of nitrate of ammonia with compressed air to obtain a solid product adapted for being immediate spread as a fertilizer.

Further it has been suggested to transform a number of different materials and solution into solid globular form by means of the so called raindrop process, in accordance with which the liquid which is to be transformed into solid globules is not spread under pressure, but is divided in some suitable manner into drops, which are permitted to fall by gravity through air or a gas, whereby they gradually solidify in the form of smooth globular bodies. In order to prepare the liquid material or the solutions for this process it has been suggested to cool the same by means of cooled metal surfaces.

Experiments have however proved that the treatment of a solution of nitrate of lime having an addition of nitrate of ammonia in accordance with the known methods is not suflicient to prepare this particular solution for the subsequent treatment in accordance with the raindrop process. H

The present invention is based on the cognition of the fact that it is possible by the use of a special kind of treatment of the concentrated solution of nitrate of lime with nitrate of ammonia to bring this solution intoa form in which it is suitable for treatment in accordance with the raindrop process. The main feature of the invention lies therein that the concentrated solution after'hav-. 40 mg been cooled and partially solidified by means of a cooled metal surface is carried to a heated homogenizing device, in which it is transformed at constant temperature into a uniform homogenized broth. This-broth is suitable for immediate treatment in accordance with the well known raindrop process.

In connection with the means for transforming the broth into drops it has been found convenient to utilize the centrifugal power. By using a centrifuge for spreading the liquid it is possible to obtain globules of substantially uniform size, which is considered an advantage in use of the product as a fertilizer. V In accordance with the invention the thickened the practical ULAR FORM Taunus, Germany,

-Elektrisk Kvaelsto Norway ebruary 16, 1933, Serial No. 657,138 Germany February 22, I932 ACTURE 0F Norway, and Carl the-Rhine, and Georg solution or broth is conveyed to a heated rotating disc, the temperature approximately equal to the temperature of the of which is maintained or somewhathigher than broth.

On the drawing an arrangement for carrying out the process in accordance with the present invention is diagrammatically illustrated by way of example. From the a solution of nitrate of ammonia and 13.3% of 100 C. the solution is storage tank a containing lime with 4.7% nitrate of water at a temperature of conveyed to a trough b,

of the cylinder by mean is conveyed to a steam h s of a scraper blade d and eated homogenizing vessel e, in which a helical conveyer f is rotating. In this vessel the homogenous broth is formed at a temperature of about 96 G g disc g, by means of which it is the heated rotatin transformed into drops the air.

. and is conveyed to falling by gravity through The new process involves agreat advantage as compared'with the previously known methods of treatmentowing to the fact that it is made possible in accordance with the present method to transform the solution of nitrate of lime with an addition of nitrate of ammonia into smooth globular bodies without any formation of dross.

In this globular form the material is advanta' geous for several reasons, amongst which may be mentioned that the ratio of the surface to the volume of the globule whereby the amount of hygroscopic product is Further the product ow lar surface is not incli er the surface and the 11 feet globular form.

We claim:

1. A process for treati lime having an additio he a machines is easier and mor s is the lowest possible, moisture absorbed by this reduced to a minimum. ing to the smooth globuned to the formation of important as well during practical use of the prod- Further the specific volume duct is lower than that of neven surfaces, whereby nsiderable saving in packthe product has a distinct er for the reason that the ugh the channels and disgricultural spreading e uniform the smoothearer the form to the perng solutions of nitrate of n ofnitrate of ammonia 1 OFFICE 2. A process as claimed in claim 1, comprising transferring the uniform homogenized broth to a heated disc rotating about a vertical axis for dividing the broth into drops of suitable size.

3. A process as set forth in claim 1 comprising transferring the uniform homogenized broth to a heated rotating disk for dividing the broth into drops of suitable size.

NICOLAI S'I'EPHANSEN. CARL EYER. GEORG MEDER. 

